"Till the time BJP was walking on the path laid down by Atal Bihari Vajpayee for the NDA coalition by keeping off controversial issues and disputed personality, we were with them... But the day they changed their track we thought it would be wise to leave," Kumar said while addressing the "Sankalp rally" here.
The BJP had promised to not do anything beyond the issues on which there was a consensus among partners of the coalition, he said.
The JD(U) leader even took potshots at the media for "too much coverage" of Narendra Modi, whose claim to fame, he alleged was developing an already developed state, and ignoring his achievements in developing a backward state like Bihar.
"A person who claims of taking forward the state (Gujarat) which was already developed is getting all the limelight while the person who develop a backward state is ignored," he said.
Slamming a Gujarat minister for linking migration from Bihar and Uttar Pradesh to surge in the number of poor in the state, Kumar said migrants on contrary contributes in the progress of these states.